Sectional key plug for locks



Dec. 27, 1932. F. E. BEST SECTIONAL KEY PLUG FOR LOCKS Filed Aug. 12. 1929 fig. 5

% %Wf w ENVENTOR Patented Dec. 27, 1932 UNITED STATES;

PATENT OFFICE I FRANK ELLISON BEST. or SEATTLE, wssmneron; Assic-nos T FRANK E. BEST, 121m,

or SEATTLR'WASI-IINGTON, A coaroanrron or wAsi-iINGroN SECTIONAL KEY PLUG on LOCKS Application filed August 12,1929. Serial No. 385,279.

My invention relates to improvements in sectional key plugs for pin tumbler locks and the general object of my invention is to provide a key plug of a standardized cross sectional shape which may be made in various different lengths to fit locks of larger or smaller size.

Another object is to provide a sectional key plug which is interchangeable for longer and shorter locks and which makes it possible to use the same key for the operation of a longer and shorter lock thus making it possible to reduce the number of keys which a person is obliged to carry.

Another object is to provide a key plug of rigid and substantial construction which has an integral head formed at both ends.

A further object is to provide a strong and rugged key plug in which the two parts of the key plug are broached from diametrically opposite sides to form a key way and in which said two parts are securely riveted together in end to end relation.

Other and more specific objects will be apparent from the following description taken in conection with the accompanying drawing.

In the drawing Fig. 1 is a plan view of a key plug constructed in accordance with my invention showing the two parts of the key plug as they might appear before being riveted together.

Fig. 2 is a fragmentary sectional view on broken line 22 of Fig. 1, showing the two parts of the key plug riveted together.

Fig. 3 is a view in cross section substantially on broken line 33 of Fig. 1.

Fig. i is an end elevation of the key plug on broken line 4-t of Fig. 1.

Fig. 5 is an elevation of a key blank of a form adapted to be used in connection with my sectional key plug.

All of the views are drawn on an enlarged scale. Like reference numerals designate like parts throughout the several views.

Referring to the drawing 6 and 7 designate the two parts of a sectional key plug of externally cylindrical shape. 6 and 7 are rigidly secured together in end to end relation by forming, on one of said parts,

These two parts two integral studs or rivets 8 which are inserted into the smaller ends 9 of longitudinaliy formed holes 10 in the other part and are then expanded and riveted or clinched by the use of a suitable tool inserted'from the outer ends of the holes 10. The studs 8 are prefer ably conically recessed in the end'as indicated by dotted lines at 12, in Fig. 1, and the larger and smaller holes 9 and 10 in the other plug part form, at their junction, an in clined shoulder 13 over which the conically recessed portions of the studs 8 may be expanded.

Screws inserted through the holes 10 and screwed into the plug part 7 could be used for securing the two parts together but would be more costly and less desirable and less accurate than the rivets.

Before the two plug parts 6 and 7 are secured together they are broached from opposite sides to form a key way. In the positions shown in the drawing the plug section 6, is broached from the top downwardly toform apart 14 of the keyway and the plug section 7 is similarly broached from the bottomupwardly to form a part 15 of the keyway. When the two plug parts are secured together these two keyway portions register so that a key formed from a blank 16 of the shape shown in Fig. 5 may be readily inserted therein. Holes 17 for the reception of the usualftumbler pins (not shown), are drilled from the broached side downwardly into the plug portion 6 and similar holcs18 are drilled from the unbroached side downwardly into the plug portion 7 Smaller ejector holes 17 and J8 extend on through the unbroached part of the plug portion 6 and through the broached part of the plug portion 7, to permit the tumbler pins to be punched ,outwhen the lock is tobe refilled. The plug portion 6 has an integral head 19 and the plug portion 7 has an integral head 20. When the two portions of the key plug are riveted together this constitutes a key plug with an integralhead on each end.

The inner end of the key plug portion 6 is designed to form the key stop 23, against which a properly positioned shou1der24 on ends.

In the drawing I have shown the key plug portion 6 as having five tumbler pin holes therein and have shown the key plug portion 7 as having three tumbler pin holes. With this arrangement the key plug portion 6 will satisfy the requirements of a five barrel lock by simply riveting a face plate onto the forward end thereof, the key 16 in this instance will have five notches in the forward end thereof which will operate the lock and the shoulder 24 will abut against the end of the key plug portion 6 and form the stop. If an eight barrel lock is to be made the key plug portion 7 is secured to the end of the key plug portion 6, the key 16 is provided with eight notches and the shoulder 24 engages the end of the plug portion 6 in the same manner. It is thus possible for a person with two locks, one a five barrel and one an eight barrel, to use the same key on both locks. In a similar way the number of tumbler pins may be varied in either one of the key plug sections to form locks of any desired number of barrels.

The foregoing description and accompanying drawing clearly disclose a preferred embodiment of my invention, but it will be understood that this disclosure is merely illustrative and that changes in this key plug may be made within the scope and spirit of the following claims.

I claim:

1. In a pin tumbler lock, a key plug formed of a plurality of sections secured together in end to end relation and embracing jointly the tumbler pin holes of said key plug and a key stop formed at two abutting ends of said sections.

2. A key plug for a pin tumbler lock embodying a plurality of sections secured together in end to end relation, said sections having keyways broached for a portion only of their diameters from diametrically opposite sides.

3. A key plug for a pin tumbler lock embodying two rigidly connected cylindrical sections having longitudinally aligned keyways of corresponding cross sectional shape cut into said sections for a portion only of their diameters from opposite sides.

4. A key plug for a pin tumbler lock embodying two cylindrical plug sections rigidly connected with each other in end to end abut- 

